Adapt linux build now depending on libssl-dev. Introduce tests job (#45, #46) (!42)

* Adapt linux build now depending on libssl-dev (#45)

native-tls transitive dependency introduced in !41
which requires libssl-dev package installed
for the build to find ssl components

Switching to non-slim Debian image which comes
with libssl-dev pre-installed

Introduce linux tests job: to run tests (#46)
and prevent similar issue in the future

Update changelog